Rotor arms for ignition distributors



Jan. 2, 1968 A. D. PRICKETT 3,

ROTOR ARMS FOR IGNITION DISTRIBUTORS Filed July 28, 1966 United States Patent 3,361,886 ROTOR ARMS FOR IGNITION DKSTRIBUTORS Alfred Donald Prickctt, Birmingham, England, assignor to Joseph Lucas (Industries) Limited, Birmingham, England, a British company Filed July 28, 1966, Ser. No. 568,560 Claims priority, application Great Britain, Aug. 11, 1965, 34,325/65 3 Claims. (Cl. 200-166) ABSTRACT OF THE DISCLOSURE A rotor arm for use in an ignition distributor includes a contact piece which in use rotates and is adapted to contact a plurality of fixed contact pieces in turn. The contact piece is carried by an insulating body, on which are printed an inductor and a resistor in series for reducing radio interference. Preferably, in order to increase the inductance of the inductor,, a dis-c of ferro-magnetic material is connected to the body but insulated from the printed circuit, or a core of ferro-magnetic material is provided which extends through but is insulated from the printed circuit.

This invention relates to a rotor arm for the distributor of a spark ignition system.

A rotor arm according to the invention comprises an insulating body adapted for connection to a rotatable spindle, a contact piece carried by the body and adapted to contact a plurality of fixed contact pieces in turn as the arm rotates, and a printed circuit on said body, the printed circuit including a central zone for engagement by a brush connected to an ignition coil, together with a conductor connecting the central zone to the contact piece and shaped to define an inductor and a resistor in series, the inductor and resistor serving to reduce radio interference.

In the accompanying drawings:

FIGURE 1 is a circuit diagram of a vehicle ignition system,

FIGURE 2 is a plan view of a rotor arm constructed in accordance with a first example of the invention,

FIGURE 3 is a plan view on the line 3-3 in FIGURE 1 and,

FIGURES 4, 5 and 6 are views similar to FIGURE 3 of second, third and fourth examples respectively.

Referring to FIGURE 1, the ignition system includes a battery B, and ignition coil C current flow in which is controlled by an interrupter I bridged by a capacitor, and a distributor D supplying sparks to the plugs P in turn. Current flows to the plugs through an inductor 8 and a resistor 9 which are incorporated in the rotor arm as shown in the remaining drawings.

Referring now to FIGURES 2 and 3, the rotor arm includes a body 11 moulded in a synthetic resin and having formed in one face thereof a blind bore 12 for engagement with the rotatable spindle of the distributor D. Secured to the opposite face of the body is a contact piece 13 which as the arm rotates co-operates with in turn a plurality of fixed contact pieces electrically connected to the plugs P. Also on said opposite face is a printed circuit 14 including a central zone 15 which in use is engaged by a spring-loaded brush 16 connected to the ignition coil C,

the zone 15 being connected to the contact piece 13 by a printed spiral conductor 17. The spiral conductor 17 acts as the resistor 9 and inductor 3 which in use act to reduce or obviate radio interference.

Referring now to FIGURES 4, 5 and 6, the inductance of the conductor may be increased if necessary by means of a disc 18 of ferromagnetic material (e.g. ferrite) mounted behind the printed circuit but insulated therefrom (FIGURE 4) or by a core 19 of the same material mounted in an axial bore in the rotor so as to extend through the printed circuit (FIGURE 5), or by a combination of both disc 18 and the core 19 (FIGURE 6).

In either of the arrangements utilizing the core 1? a conductive cap 21 covers the projecting end of the core 19 but is insulated therefrom, the cap 21 being engaged by the brush 16 in use and connected by soldering, to the conductive part of the printed circuit.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A rotor arm comprising an insulating body adapted for connection to a rotatable spindle, a contact piece carried by the body and adapted to contact a plurality of fixed contact pieces in turn as the arm rotates, and a printed circuit on said body, the printed circuit including a central zone for engagement by a brush connected to an ignition coil, together with a conductor connecting the central zone to the contact piece and shaped to define an inductor and a resistor in series, the inductor and resistor serving to reduce radio interference.

2. A rotor arm for an ignition distributor comprising aninsulating body adapted for connection to a rotatable spindle, a contact piece carried by the body and adapted to contact a plurality of fixed contact piece in turn as the arm rotates, and a printed circuit on said body, the printed circuit including a central zone for engagement by a brush connected to an ignition coil, together with a conductor connecting the central rotor to the contact piece and shaped to define an inductor and a resistor in series, the inductor and resistor serving to reduce radio interference, and the arm further including a disc of ferromagnetic material insulated from the printed circuit for increasing the inductance of said inductor.

3. A rotor arm for an ignition distributor comprising an insulating body adapted for connection to a rotatable spindle, a contact piece carried by the body and adapted to contact a plurality of fixed contact pieces in turn as the arm rotates, and a printed circuit on said body, the printed circuit including a central zone for engagement by a brush connected to an ignition coil, together with a conductor connecting the central rotor to the contact piece and shaped to define an inductor and a resistor in series, the inductor and resistor serving to reduce radio interference, the rotor arm further including a core of ferromagnetic material extending through but insulated from the printed circuit for increasing inductance of said inductor.

References Cited UNITED STATES PATENTS 1,997,460 4/1935 Fitzsimmons 20019 ROBERT K. SCHAEFER, Primary Examiner. ROBERT S. MACON, Examiner. H. O. JONES, Assistant Examiner. 

